CAN PACKAGING, CAN PACKAGING BLANK AND APPARATUS AND METHOD FOR PRODUCTION THEREOF

Abstract

The invention relates to an apparatus for producing a can packaging blank by backward extrusion. The apparatus has a die wall and an extrusion punch, wherein the die has a die base and a die wall having a die wall height HG. The die wall has, in the region thereof adjacent to the die base, at least one protrusion having predetermined width (B), predetermined height (H), predetermined depth (T) and predetermined cross-section, wherein the height (H) of the protrusion equals 95% of the die wall height (HG) at maximum.

Claims

1. A device for the production of a can packaging blank by reverse extrusion, wherein the device comprises a die and a punch, and wherein the die comprises a die bottom and a die wall with a die wall height, that the die wall comprises in a region adjacent to the die bottom at least one projection with a predetermined width, a predetermined height, a predetermined depth and a predetermined cross-section, wherein the height of the projection amounts to a maximum of 95% of the die wall height.

2. The device according to claim 1, wherein the die wall comprises a plurality of projections in the region adjacent to the die bottom.

3. The device according to claim 1, wherein the plurality of projections have a different width and/or a different height and/or a different depth and/or a different cross-section, wherein the height of each of the plurality of projections amounts in each case to a maximum of 95% of the die wall height.

4. The device according to claim 1, wherein the at least one projection has a width of 0.1 mm to 10 mm.

5. The device according to claim 1, wherein the at least one projection has a height of 0.1 mm to 30 mm.

6. The device according to claim 1, wherein at least one projection has a depth of 0.01 mm to 1 mm.

7. The device according to claim 1, wherein at least one projection has a cross-section parallel to the die bottom, and wherein the cross-section has a triangular, rectangular, trapezoidal, circle segment-shaped, or semicircular form.

8. The device according to claim 1, wherein the at least one projection is arranged circumferentially around an entire circumference of the die wall.

9. The device according to claim 1, wherein the die bottom is formed circular, oval, rectangular, square, triangular or polygonal, and wherein the die wall is arranged vertically on the die bottom.

10. A method for the production of a can packaging blank by reverse extrusion, comprising the steps a) provision of a device according to claim 1, b) insertion of a circular blank having a thickness into the die, c) introduction of a punch and exertion of a pressing force on a circular blank, and d) removal of the can packaging blank from the die.

11. The method for the production of a can packaging blank according to claim 10, wherein the at least one projection provided in a region of the die wall adjacent to the die bottom has a predetermined height wherein the predetermined height amounts to a maximum of 95% of the thickness of the circular blank.

12. The method for the production of a can packaging blank according to claim 10, wherein the at least one projection provided in the region of the die wall adjacent to the die bottom has a predetermined height, wherein the height amounts to at least 5% of the thickness of the circular blank.

13. A can packaging blank with a main axis defining a longitudinal direction and a wall comprising an outer side and an inner side, wherein the wall has a variable wall thickness at least over a partial region of the can packaging blank extending in the longitudinal direction, wherein the partial region of the can packaging blank with a variable wall thickness, starting from a bottom of the can packaging blank, extends over a maximum of 95% of a height in the longitudinal direction of the can packaging blank and that the variable wall thickness is brought about by the fact that only the outer side of the wall is constituted in a relief-like manner.

14. The can packaging blank according to claim 13, wherein the partial region of the can packaging blank with a variable wall thickness, starting from the bottom of the can packaging blank, extends over a maximum of 75% of the height in the longitudinal direction of the can packaging blank.

15. The can packaging blank according to claim 13, wherein the partial region of the can packaging blank with a variable wall thickness, starting from the bottom of the can packaging blank, extends over at least 5%, of the height in the longitudinal direction of the can packaging blank.

16. The can packaging blank according to claim 13, wherein the relief-like formation of the outer side of the wall includes groove-like depressions, wherein the groove-like depressions run parallel to the main axis.

17. A can packaging blank produced according to the device according to claim 1.

18. A can packaging blank produced according to the method according to claim 10.

19. A can packaging produced from the can packaging blank according to claim 13.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The invention will be explained in greater detail below with the aid of examples of embodiment in connection with the drawings. In the figures:

[0058] FIG. 1 shows in a diagrammatic representation a vertical cross-section through a die known from the art;

[0059] FIG. 2 shows in a diagrammatic representation a vertical cross-section through a device according to the invention for the production of a can packaging blank by reverse extrusion;

[0060] FIG. 3A shows in a diagrammatic representation a die according to the invention in a side plan view;

[0061] FIG. 3B shows in a diagrammatic representation a detail of the die according to FIG. 3A in a plan view;

[0062] FIG. 4A shows in a diagrammatic representation a can packaging blank according to the invention in a side plan view;

[0063] FIG. 4B shows in a diagrammatic representation a magnified detail of a cross-section along plane A-A of FIG. 4A; and

[0064] FIG. 5 shows in a diagrammatic representation a can packaging according to the invention produced from the can packaging blank according to a FIG. 4A in a side plan view.

DETAILED DESCRIPTION OF THE INVENTION

[0065] FIG. 1 shows in a diagrammatic representation a vertical cross-section through a die 2 known from the prior art. Punch 3, die 2 with die bottom 2.1 and die wall 2.2 are shown. Punch 3 comprises a circumferential bead 5

[0066] In the left-hand part of FIG. 1, punch 3 is represented spaced apart from die 2, i.e. the situation before the formation of the can packaging blank. Circular blank 6 is inserted into die 2.

[0067] In the right-hand part of FIG. 1, punch 3 is introduced into die 2 and exerts pressure on the circular blank 6. As a result of this compressive loading, a deformation of circular blank 6 occurs, which flows upwards opposite to the direction in which the punch is moving. The wall thickness of the can packaging blank formed by reverse extrusion is defined by the gap remaining between circumferential bead 5 of punch 3 and die wall 2.2.

[0068] FIG. 2 shows in a diagrammatic representation a vertical cross-section through a device according to the invention for the production of a can packaging blank by reverse extrusion. The representation is similar to the device known from the prior art shown in the left-hand part of the FIG. 1. Punch 3, die 2 with die bottom 2.1 and die wall 2.2 are shown. Punch 3 comprises a circumferential bead 5. Die wall 2.2 comprises in its region adjacent to die bottom 2.1 a plurality of projections 4 with a width of 1 mm, a height H of 1.5 mm, a depth of 0.15 mm and a cross-section formed trapezoidal parallel to die bottom 2.2.

[0069] Circular blank 6 is inserted into die 2. Circular blank 6 is made of aluminium and has a thickness HR of 4.5 mm. The height of die wall HG amounts to 6 mm. The height of projections 4 thus amounts to 25% of the height of the die wall. Circular blank 6 lies on projections 4 before the introduction of punch 3. Punch 3 is then introduced into die 2 and exerts pressure on circular blank 6. The circular blank material is then first pressed downwards up to die bottom 2.2 and is then in contact with projections 4 over height H of 1.5 mm. Since thickness HR of the circular blank is a factor of 3 greater than height H of projections 4, the groove-like depressions in the wall of the can packaging blank thus formed by reverse extrusion extend over a third of the extension of the can packaging blank in longitudinal direction LR (see FIG. 4A).

[0070] FIG. 3A shows in a diagrammatic representation a die 2 according to the present invention in detail in a side plan view. Die 2 with die bottom 2.1 and die wall 2.2 is shown. Die wall 2.2 comprises in its region adjacent to die bottom 2.1 a plurality of projections 4. Projections 4 have a width B of 5 mm, a height H of 10 mm, a depth of 0.15 mm and a cross-section formed trapezoidal parallel to die bottom 2.2. The edges of projections 4 adjacent to die bottom 2.1 are, beveled i.e. do not project perpendicular from die wall 2.1, but rather run at an angle of around 45 relative to die wall 2.1.

[0071] Depth T of projections 4 of 0.15 mm can be seen from the detail of the die according to FIG. 3A shown in plan view in FIG. 3B in a diagrammatic representation.

[0072] All projections 4 of the embodiment of the die according to the invention shown in FIGS. 3A and 3B have the same height, width, depth and the same cross-section and are arranged distributed equidistant from one another spaced apart uniformly around the entire circumference of the die wall.

[0073] FIG. 4A shows in a diagrammatic representation a can packaging blank 10 according to the invention in a side plan view. A magnified detail of the cross-section along plane A-A of FIG. 4A is shown in a diagrammatic representation in FIG. 4B. Can packaging blank 10 has a main axis HA defining a longitudinal direction LR and a cross-sectional area arranged normal to main axis HA, wherein wall 12 of can packaging blank 10 comprises an outer side 12.1 and an inner side 12.2. Over a partial region TB of can packaging blank 10 extending in longitudinal direction LR, wall 12 has a variable wall thickness WD in the cross-sectional area of can packaging blank 10, which is brought about by groove-like depressions 11 in outer surface 12.1, wherein inner surface 12.2 runs continuously over the region of groove-like depressions 11. Depth T of groove-like depressions 11 corresponds to depth T of projections 4 of 0.15 mm (see FIG. 3B).

[0074] Grooves 11 of can packaging blank 10 formed by projections 4 of die 2 have the same height, width, depth and the same cross-section and are arranged distributed equidistant uniformly spaced apart from one another around the entire circumference of can packaging blank 10.

[0075] FIG. 5 shows in a diagrammatic representation in a side plan view a can packaging 20 according to the invention which is produced from can packaging blank 10 according to FIG. 4A. Proceeding from can packaging blank 10 according to FIG. 4A, only the post-processing of the opening of can packaging blank 10 facing away from the can packaging bottom and known to the person skilled in the art was carried out to produce finished can packaging 20. This includes for example the formation of the can shoulder and the flanging of the can packaging wall at its opening for the formation of rolled edge 21.

[0076] While the invention has been shown and described, it will be understood that there is no intent to limit the invention by such disclosure, but rather, is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention.

LIST OF REFERENCE NUMBERS

[0077] 1 Device [0078] 2 Die [0079] 2.1 Die bottom [0080] 2.2 Die wall [0081] 3 Punch [0082] 4 Projection [0083] 5 Bead [0084] 6 Circular blank [0085] 10 Can packaging blank [0086] 11 Groove-like depressions [0087] 12 Wall [0088] 12.1 Outer surface of the wall [0089] 12.2 Inner surface of the wall [0090] 20 Can packaging [0091] 21 Bead [0092] B Width of the projection [0093] H Height of the projection [0094] T Depth of the projection [0095] HG Height of the die wall [0096] HR Thickness of the circular blank [0097] HA Main axis of the can packaging blank [0098] LR Longitudinal direction [0099] TB Partial region of the can packaging blank [0100] WD Wall thickness of the can packaging blank